Phonographic system



Feb. 7, 1939. C, T. JACOBS 2,146,434

PHONOGRAPHI C SYSTEM Filed April 15, 1936 2 Sheets-Sheet l I INVENTORCrz arfes 7? Jacobs BY ATTORNEY Feb. 7, 1939. c T J B 2,146,434

PHONOGRAPHIQ SY STEM Filed April 15, 1936 2 Sheets-Sheet 2 509 day L.505 .503

INVENTOR Charles 7. Jacobs BY 592. M

ATTORNEY Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE PHONOGRAPHICSYSTEM.

Application April 15, 1936, Serial No. 14,449 20 Claims. (Cl. 274- 18)This invention relates to phonographic systems, and more particularly tomeans and methods for controlling and indicating the operation thereof.

While not in all aspects limited thereto, the invention has especialreference to systems comprising a plurality of phonographs adapted foralternate, or sequentiaLoperation to provide uninterrupted recordationof continuing matter. The control means most particularly contemplatedby the instant invention are such asmay be manipulated, for example, bya dictator, at a point remote for example successively supplying thephonographs with fresh records and restoring them to recordationinitiation conditions, as required.

' A system according to the invention desirably,

though not indispensably, may involve the use for each phonograph ofstartingand stopping means of the type responsive to momentaryactuation- 20 such for example as shown and described in connection withsuch systems in the co-pending application of Charles Heunlich, SerialNo. 581,870, filed December 18, 1931, on which Patent No.

2,042,228 has since been issued. As is known,

25 having been therein shown, the employment of such means in a systemof sequentially operating phonographs is attended with the danger, ifuncounteracted, of a start-stop oscillation under certain conditions ofportions of the system. An ob- 30 ject of the instant invention is theprevention, in

novel and improved manner, of such oscillation.

Another object is the provision of improved and reliable protectivemeans for a system of the class described.

35 Another object of the invention is the arrangement of appropriatecontrol system elements for plural phonographs in a novel and simplemanner.

Another object is the arrangement of such elements in mannerfacilitating the association therewith of appropriate indicating meansfor both dictator and attendant.

Another object is the provision of a simplified such control system.

Another object is the provision of a control system involving aparticularly small number of conductors joining the dictator's controlstation with the phonographs proper.

Another object is the provision of a generally 50 improved pluralphonograph systemfparticularly for sequential phonograph operation.

Still another object is the provision of more extensive indications tothe attendant of the condition of the system, and of improved means to55 providing indications for the attendant.

from the phonographs proper, an attendant then Still another object isthe Simplification of the indicating means for the dictator.

Still another object is the provision of generally improvedandsimplified indicating means in a system of the class described. 5Other and allied objects will more fully appear from the followingdescription and the appended claims.

In the description reference is had to the accompanying drawings, ofwhich:

Figure l is a schematic diagram of an embodiment of my invention in asystem of two phonographs and control station therefor;

Figure 2 is a like diagram of an alternative embodiment of my invention,some of the components of the control station appearing in crosssection;and

Figure 2a is a fractional control station view intended for optionalsubstitution for the corresponding portion of Figure 2, illustrating amodification thereof.

Reference is first invited to Figure 1, wherein have been illustratedthe plurality of phonographs comprising phonographs A and B, the controlstation 0, and the phonograph coupling .unit D. .The phonographs propermay first be described, with particular reference to phonograph A; itwill be understood that phonograph B is mechanically similar, itsillustrated components having been designated with numbers similar tothose for the corresponding components of phonograph A, excepting thatthey have been furnished with prime marks. Each phonograph may comprisefor example a mandrel l0 adapted to carry a cylindrical record; a soundbox I adapted to record on and/or reproduce from such a record andadapted to be driven longitudinally thereof as along a guide 8 by meansof feed screw 8a; and a motor M suitably arranged to produce rotationalmovement of the mandrel and longi- 40 tudinal movement (in a right-handdirection as illustrated) of the sound box. The sound boxes may be ofany known variety, as may also the means for energizing the same-notshown herein because forming no part of the instant invention.Optionally there may also be included in each phonograph a clutch Linterposed between themotor and the parts thereby moved; it is to beunderstood, however, that the illustrated inclusion of these clutcheshas not rendered the system as shown a completely clutch-controlled one.

In respect of general elements and their coordination, the controlarrangements illustrated for the system may be described as comprisingseparate operation control members for the sev- Y.

to employ for this purpose, andhave schematical- 2 eral phonographs, anda common operation control member for all the phonographs, these beingso arranged that each phonograph will operate only when both therespective individual member and the common member occupy their run"positions, and will be stopped when either the 1'61 spective individualmember and/or the common member occupies its "stop" position; anautomatic system, including starting and stopping circuits, energizableto position the individual conture portion 28 arranged for alternateattraction by the magnets; and the switch conveniently includes the,control arm itself as a pole, connected for example to the positiveconductor I2a,

and a pairof contacts 22 and 23 respectively in series with the stop andstart magnets 20 and 2|, the control arm having two possible positionsonly-i. e.,"touching one or the other of the contacts. The actuation ofeach magnet is effected through the switch; and it will be seen that thecontacts are so arranged that the control arm comes to a positiontouching one (e. g., in-

phonograph A, touching contact 22, in series with stop magnet 20) inresponse to actuation of the.

respectively opposite magnet (e. g., start magnet 2|), the latter magnetbeing thereby open-cirpreventing objectionable eflects otherwise tendingto occur when the system becomes temporarily incapable of furtherrecordatlon, as by virtue of all sound boxes being at or adjacent theirterminal travel limits.

The supply of current for the entire system may be derived from anysuitable supply line as through the plug it, rendering at respectivelyopposite line potentials the The conductor 82 has been shown leadingonly to the pole Nb of the main line switch it in the control stationQto the co-operating contact spring Me of which is connected theconductor 02a leading from the control station into the coupling unitand thence into each phonograph; the conductor 82a is of course investedwith the potential of conductor i2 when the switch it is closed (e. g.,pole llb touching contact spring of Na), which will be balance of thedescription. in the balance of the description as to Figure 1 to assumeoperation of'the system on direct current, so that typical simultaneouspolarities of several of the conductors may be noted in the figure andreferred to; it will be understood, however, that this procedure ispurely to facilitate the exposition of the circuit functions, and is inutterly no sense limitative to the indicated polarities or to directcurrent operation. In accordance with this procedure, conductor ll maybe considered the negative line conductor, and conductor I! (togetherwith l2a when switch II is closed) the positive one. The individualcontrol member for each phonograph may be an arm 21 therein, immediatelyresponsive to a magnet assembly I00 and therethrough to the automaticsystem of starting and stopping circuits hereinafter described. Eachmagnet assembly may comprise a pair of stop and.

start electromagnets (20 and 2|, respectively), the control arm beingresponsive in its position to the last actuated of the two magnets;preferably the magnet assembly has associated therewith a switcharranged upon each control arm response to open-circuit the magnet towhich the response has occurred. A variety of .systems are obviouslyavailable for the control arm, magnet assembly and switch; but I havepreferred ly illustrated, a system which is in accordance with theteachings "of U. 8. Letters Patent to Langley, No. 1,380,486, issuedJune '7, 1921. -Herein the control arm 21 comprises an armaassumedthroughout the It is also convenient conductors ii and i2.-

cuited at its,series contact (e. g., 23). This arrangement, wherein eachmagnet upon actuation both throws the control arm and open-circuitsitself, has among its distinct advantages those of obviating wastefuland excessively heating continuations of current flow through themagnet, and of enforcing a strictly alternate actuation of the twomagnets.

The run position of the control arm is that which has been illustratedin phonograph A; in that phonograph the start magnet 25 has last beenactuated to attract the arm, and the stop 'magnet series contact 22 isbeing touched by the arm (the respectively opposite arm position andconditions having been shown as obtaining in phonograph B). Therefore torender each control arm efiective to permit operation of the re spectivephonograph only when it is in the run po sition, the power supply to oneside of the respective motor may be taken from the positive conductor Moto that motor side through the con trol arm (e. g., 21) and the stopmagnet series contact (e. g., 22); each motor is thus deprived of powerwhen the respective control arm is in its stopposition, touching contact23, and the respective phonograph is accordingly then out ofoperation-he, its mandrel is stationary. It is permissible, however, tomake the electrical con nection of the mentioned side of each motor tothe conductor l2a directly, and to rely for the function of therespective control arm on a mechanical connection thereof to therespective one of the optionally included clutches. This connection hasbeen schematically illustrated in each phonograph as a lever 26 or 26';when the control arm and hence the lever are to the left (as shown inphonograph B) the clutch will be understood to be disengaged, and whento the right (as in phonograph A) the'clutch willbe understood to beengaged.

The other side of each of the motors may be connected to a commonconductor llb (shown in Figure 1 as a heavy line) and it may be thefunction of the common control member above mentioned to connect anddisconnect this conductor to and from the negative line conductor H. Thecommon control member in Figure 1 has been shown as the arm 321(connected to negative conductor H) of a magnet assembly or relay 400contained in the coupling unit D; this magnet assembly 400 may includecomponents respectively similar to all those of the magnet assembly I00above described, these having been designated with numerals higher ineach instance by 300 than those of that assembly. An appropriate contactco-operatlng with the arm 321 is to be connected to the conductor llb sothat following actuation of the start and stop magnets 32I and 320,respectively, the conductor llb will be connected to and disconnectedfrom the conductor I|. While the stop magnet series contact 322 may beemployed for this function, I prefer to employ a separate contact 322binsulated therefrom-but in such alignment therewith that when arm32I(which may be appropriately lengthened, for example) is in its runposition touching contact 322 it is also touching contact 322b.

The magnet assembly 400 may be controlled by a pair of openly biasedswitches in the control station, each having one terminal connected tothe positive conductor I2a-a stopping switch 380 having its secondterminal connected to the non-contact extremity of stop magnet 320through conductor 380a, and a starting switch 38| having its secondterminal connected to the noncontact extremity of start magnet 32Ithrough conductor 38Ia. It being borne in mind that the internalfunctioning of the magnet assembly 400 is quite like that set forth forthe magnet assembly I00, it will be seen that so long as common controlarm 32'! is in run position (preparing the stop magnet for actuation)momentary closure of stopping switch 380 will throw it to stop position,breaking the supply of power vto the motors; while so long as commoncontrol arm 32'! is in stop position (preparing the start magnet forenergization) momentary closure of starting switch 38| will throw it torun position, re-connecting conductor III) with conductor stopping andstarting switches 380 and 38I, respectively having for example themanipulating buttons 38% and 38Ib, carried by the respective pivotedpoles 380a and 38Ic, may obviously be arranged if desired with thesepoles in rigid mutual alignment about a single pivot, or otherwise toform an intermediately biased single pole, doublethrow switch.

It may here be noted that while the dictator will usually stop operationof the system by momentarily pressing the stop switch button 380a,throwing the common control arm 321 to stop position, he may at timessimply open the main line switch I4, leaving control arm 321 in runposition. In the latter case only, simple re-closing of the switch I4would cause an immediate and probably premature operation of the system.

In order to insure the assumption by controlarm 321 of stop positionupon stopping of the system, however effected, a spring contact I40 maybe associated therewith, untouched by pole |4b when switch I4 is closedbut, in the process of opening of switch I4, touched by the pole Mbbefore the latter leaves contact with spring Ha. This extra springcontact Me is connected to the conductor 380a, so that the connection ofthis conductor to I21: before opening of switch I4 is insured; this isobviously equivalent to the momentary closing of switch 380, and thusthrowing of the control arm 321 upon any stopping of the system isinsured.

Attention may now be directed to the automatic system of stopping andstarting circuits. The stopping circuit for each phonograph is a localcircuit therein, including the respective stop magnet (20 or 20) andswitch means arranged to be closed (and thus to actuate the stop magnet)as the sound box reaches its terminal travel limit; while the startingcircuits extend between the several phonographs, this circuit for eachphonograph including the respective start magnet (2| or 2 I) and switchmeans associated with another of the phonographs and arranged to beclosed when the sound box in such other phonograph approaches itsterminal travel limit-this closing of the circuit actuating the startmagnet included in the circuit. Such automatic system of starting andstopping circuits is in itself well known; but I associate therewith anovel protective circuit, having switch means in each phonographassociated with the automatic system switch means therein, theprotective circuit co-operating with the starting and stopping circuitsto prevent certain misfunctionings of those circuits as will hereinafterbe apparent.

The switch means in each phonograph for stopping, starting andprotective circuits may comprise a group of three normally open switchesadapted to be progressively closed as the sound box in that phonographapproaches its terminal travel limit; these switches, in the order oftheir closings, may be termed the protective switch, the successivestarting switch, and the selfstopping switch. They have been illustratedin each phonograph as formed by five contact springs (e. g., 6, 5, 3, 2,I in phonograph A); spring 6 being adapted upon rightward movement to beclosed against spring 5, spring 5 being connected with spring 3 by aninsulating tierod or -block b, and spring 3 being adapted (by continuedrightward movement of spring 6) to be closed against spring 2 andfinally (through spring 2) against spring Springs 5 and 5 together formthe protective switch 56, and springs 3 and (mutually closeable throughspring 2) form the self-stopping switch 3|, for the phonograph withwhich they are associated; while springs 3 and 2 togetherform thesuccessivestarting switch 32 for another phonograph. The spring 6 isadapted for rightward movement (to close successively the severalswitches) as the sound box approaches its terminal travel limit,

as by a projection 9 therefor provided on the sound box and adapted toimpinge against spring 6. The description of the switch means has beengiven specifically with reference to phonograph A; but it will of coursebe understood that corresponding switch means, sound box projection,etc. are provided in phonograph B, their designating numerals beingprovided with prime marks.

To energize the automatic system contact springs 3 and 3' are connectedto the negative conductor II. (For reasons hereinafter apparent thisconnection is desirably made through the switch formed by contact322b-and common control member 32Ii. e., through conductors Ho and Ho toconductor ||bso that it will be effective and the automatic systemenergized only when control member 32! occupies its run position.) Thecontact springs I and I are respectively connected to the non-contactextremities of the stop magnets 20 and 20 through the respectiveconductors 54 and 54'. The stopping circuit for phonograph A may betraced from spring 3 to the positive conductor |2a through theself-stopping switch 3|, conductor 54, stop magnet 2|], contact 22, andcontrol arm 21. Analogously the stopping circuit for phonograph B may betraced from spring 3' to the positive conductor |2a through theself-stopping switch 3|, conductor 54, stop magnet 20', contact 22', andcontrol arm 21'.

- Contact spring 2 (in phonograph B) is connected to the non-contactextremity of start magnet 2| (in phonograph A) through the conductor 40,and analogously contact spring 2 (in phonograph A) is connected to thenon-contact extremity of start magnet 2| (in phonograph B) through theconductor 40,; both these conductors 40 and 40' may conveniently passthrough the coupling -61! repeated, but in each unit D. The startingcircuit for phonograph A T may be traced from spring 3' (in phonographB) to the positive conductor l2a through the successive starting switch32', conductor 40, start mag- 5 net 2|, contact 23, and control arm 21.Analogously the starting circuit for phonograph B may be traced fromspring 3 (in phonograph A) to the positive conductor 12a through thesuccessive starting switch 32, conductor 40, start magnet 2!, contact23', and control arm 21.

The operation of the automatic system may be described on the initialassumption, that the common control member 321 is in run position; thatone of the phonographs (e.- g., A) is in operg ation, with its sound boxat some intermediate point in its rightward travel; and that thephonograph B is out of but in readiness for, operationi. e., has itssound box at its initial or leftward travel limit and has a freshrecordinserted upon 20 its mandrel. Since the phonograph A is inoperation, its control arm'2l is of course in its run position,completing its motor circuit and placing the stop magnet 20 in conditionfor next actuation. In phonograph B, out of operation, the arm 5 21' haslast been attracted by the stop magnet 20' to occupy its stop position,placing thestart magnet 2i" in condition for next actuation. Theseconditions are those illustrated in Figure 1.

When the sound box projection of the now oper- 30 ating phonograph Aimpinges againstthe spring contact 6 there is first closed the switch5b, of which the function is hereinafter described. Up-

on negligible further travel of the sound box .71 the spring. contact 6will have been sufiiciently as further movedto close the successivestarting switch 32; this closes. the phonograph B starting circuit,actuating the phonograph B start magnet 2i and moving-the control armZ'l' to its run position touching contact 2'; this places the mphonograph Bin operation. For a brief interval at this juncture bothphonographs will be operating, so that a slight overlap of therecordations by the two phonographs will be effected. Still furtherslight travel of the phonograph A sound 1101: E closes the self-stoppingswitch 3i, closing the phonograph A stopping circuit, actuating the stopmagnet 26, and moving the control arm Zl to its stop position touchingcontact 23; this places the phonograph A out of operation. Before the 50phonographB sound box 'l'approaches the spring contact 6' the phonographA sound boxl may be manually moved leftwardly to the beginning 1 of itspath of travel, and a fresh record inserted ulwnmandrel ill.

The conditions of the two phonographs as to operation and componentpositions will now be seen-to be quite reversed from those assumed atthe beginning of the preceding paragraph; and the operations of-thatparagraph are accordingly case as to the respectively oppositephonograph and components. -And upon completion of those operations asto that V phonograph and components, the operations preclsely asdescribed in the preceding paragraph are repeated; and so on in anautomatic progression which so long as common control member 315 remainsin run position will be unbrokenexcept by the failure to restore one ofthe sound boxes leitwardly to the beginning of its travel path duringthe travel of the other sound box.

If this failure occurs the system will, in the absence of an appropriatepreventive, go into an oscillatory condition. This is readily understoodby first supposing the sound box of phonograph B, forexample, to havereached its terminal travel limit, to have closed the switches 56' and3!,

starting phonograph A, and finally to have closed switch 3|, thus havingcaused control arm 21' to throw to its stop p sition, stoppingphonograph 5 B and preparing the start magnet 2| thereof for actuation;these conditions are those illustrated in Figure 1 excepting that theyinvolve a rightward sound box position and closed switch 56'- 32'-3l'condition in phonograph B. Now when the sound box in phonograph A hasprogressed to a near-limiting position it will close successive startingswitch 32 and thus the phonograph B starting circuit; and so there willbe actuated the phonograph B start magnet 2|, throwing the 13 controlarm 21' to run position and preparing its stop magnet 20' for actuation.Since self-stopping switch 3| in phonograph B is closed, this stopmagnet actuation will immediately occur, throwing the control arm, 21back to stop 9081- 20 tion. But because successive starting switch 8&

is still closed, a re-throwing of arm 21' to run position willimmediately occur-and so the arm throwing continues in a sustainedoscillation. And almost immediately after closing successive startingswitch 32, the continued phonograph A sound box movement will close theA self-stopping switch 28, whereupon it will readily be seen that therewill'be setup a similar start-stop oscillation of the phonograph Acontrol arm 2?. This oscillation will not only comprise an oscillationof each of the control armsiZl and El (and clutches if employed), butalso with the circuit as shown. if conductor i lb remains meanwhileconnected to the supply line, will comprise a start-stop oscillation ofeach of the two motors.

It is known to obviate this oscillation by auto= matically opening thestarting circuit of each phonograph before the stopping circuit thereofis closed. This is an efiective procedure; but it results, at the timeswhen start-stop oscillation would otherwise occur, in occupation by allthe control arms (El, 271') of their stop positions. This fact verymaterially afiects the necessary arrangements for the placement of thesystem in further operation after sound box restoration-an action whichshould of course occur not merely upon restoration of the sound boxes totheir initial travel limits, but rather thereafter in response to adeliberate manipulation bythe dictator at the control station-andrenders unusable the extremely simple such arr u einents which I haveshown.

The protective circuit which iincorporate in the system or phonographsprevents this startstop oscillation in a difierent manner: it stops theFentlre system when there is reac a condition of adjacency of both soundboxes to their. terminal travel limit, acting just before the latter ofthe sound boxes to reach such position closes the successive startingswitch re= to closing or,the circuit, for stopping such phonograph asls'then in operation. For conservation of components and, moreimportantly, for ren- 'derlng entirely similar thesubsequent startingmanipulation required of the dictator whether the system was stoppedbyhis deliberate closing of switch 380 or by the action of theprotective circuit, this device may bet-the common control armj21. Forfurther conservation of components the means for throwing this arm' tostop position in response to closing of the protective circuit may bethe stop magnet 320. Accordingly the protective circuitwhich may beginat the point P (on conductor l2a) in phonograph B and may be tracedserially through conductor 51, protective switch 56, 'conductor 51a,protective switch 56, and conductor 51b-may from the conductor 51b beconnected (as at the point Q) to the non-contact extremity of the stopmagnet 320.

Because of its functioning in the protective circuit the magnet 320 willpreferably after actuation remain energized (as long as the protectivecircuit is closed) to insure the maintenance by the arm 321 of its stopposition; this is preferred in order to obviate the re-throwing of thearm to run position by closure of the dictators starting switch 38!before sound boxrestoration (and to obviate the production of start-stoposcillation of the magnet assembly 490 by any prolonged closure of theswitch 3). It is not, however, necessary that this continuedenergization be of the full strength of the initial actuation of thismagnet; by its initial actuation'and the throwing of arm 321, thearmature 323 has been brought near this magnet,-and a relatively weakcontinued energization will be sumcient to obviate re-throwing of thearm'321 in response to any actuation of start magnet 32L Accordingly aresistance 395 may be shunted from arm 321 to contact 322, so that it isshorted when arm 321 is in run position but is rendered effective to cutdown the current through the-stop magnet 32!! and the protective circuitwhen arm 321 is in stop position. It will of course be obvious that thiswill result in'continued reduced-strength energization of the stopmagnet 32!! after any actuation thereof by closing of the dictatorsstopping switch 380, so long as that switch is held closed; but this isquite permissible in view of the reduced strength of the energization(as well as, of the short periods for which this openly biased switchwould be so held)'. 1 v

For reasons having to do with the indicating system hereinafterdescribed, it is desirable that some of the resistance which functions.to cut down the continued current flow in the protective circuit beinserted in that circuit properfor example in the conductor 5117.Accordingly it is preferred that not all the permissible resistance becomprised in 395, but that a portion 1 thereof be inserted; as 396, inthe mentioned conductor. (Typically the values of 395 and 396 are soapportioned that the total impedance of 395 and-that of the stop magnet320 will approximate that of the resistance 395.) The resistance 395,when employed, is of course to be shorted out when the control arm 321is in runposition; ac-

cordingly there may be shunted about resistance 395 a switch formed byan arm 391 mechanically linked to that control arm for movementtherewith, and a contact 399 against which the arm 391 closes when'control arm 321 is in run position.

It will now be seen that the protective circuit stops the operation ofthe motors, by throwing the common control arm 321 to stop position,before the automatic system abortively tries to start the operation ofan unstartable phonograph. Thus start-stop oscillation of the motors iseffectively prevented and, even though the automatic system weremaintained continuously energized,

assembly oscillation; it is for this and other precautionary reasonsthat the contact springs 3 and 13 are connected to conductor ll throughcontact 3221) and common control arm 321-the protective circuit uponclosing thus functioning to de-energize the automatic system as well asto preclude operation of any phonograph.

It is to be notedthat the system invariably stops-upon throwing ofcommon control arm 321 to stop position, whether effected by thedictators stopping switch 389 or by the protective circuitwith theindividual control arm of the last-operating phonograph in run position(or, in the more exceptional case of arm 321 having been thrown during aperiod of overlap, with the control arms of the two phonographs both inrun position). It is this which limits the operation required forre-starting to re-throwing of common control arm 321 only (i. e., bymomentary closure of dictators starting switch 381) operation willthereupon be automatically resumed of that phonograph (or phonographs)which were operating at the moment of prior system stopping. It isconvenient to bear in mind that whenever the arm 321 is in run positionthere is in operation one (or during overlaps, two) of the phonographs,as well as the fact that there always remains in run position at leastone of the individual control arms (21, 21').

It has been seen that a continued closure of the protectivev circuitrenders the closing of dictators starting switch 380 inefiective tovrethrow common control arm 321 to run position until the closure isbroken by the restoration of at least one sound box; thus anon-operation of the system is enforced during that circuit closure.

In order that the dictator be apprized (preferably.

, trol station; at the same time it is desirable that this be done witha minimum of complication of the system and without extra conductors tothe control station, and generally in a manner resulting inindicationsof a high degree of positiveness. Such indicating means,appropriate to .the system disclosed, are shown in Figure 1. These meansmay comprise two pilot lamps 260 and 290, which may respectively betermed stand-by and phonograp pilots; the stand-by pilot desirably islit whenever the main line switch I4 is closed and the system is eitherin operation, or out of but in' readiness for operation, while thephonograph pilot is desirably lit whenever either of the phonographs isoperating. These lamps are preferably of the neon type, designed foroperation with very minute current, and (at least in the case ofthe'stand-by pilot 260) preferably have a 'minimum igniting voltagematerially in excess of course assuming line switch ll closed) thepotential of conductor 380a, however, varies in accordance with thecondition of the system. If the control arm 321 is in run position andthe system thus in operation, it is obvious that the conductor 380a isestablished through stop magnet 320 at negative line potential;accordingly (in view of the very high resistance of 260 subother hand,if the control arm 927 has come into stop position in response to aprotective circuit closing which persiststhe system thus not being inreadiness for further operation-the conductor 380a is established atapproximately mid line potential, in view of the division of linevoltage between resistance 396 on the one hand and the resistance 395and stop magnet 320 on the other hand accordingly only approximatelyhalf line potential appears between conductors Rd and 380a, and thepilot 266 will be extinguished. And if the line switch ll be opened, thepilot 260 will obviously be extinguished. So the times of lighting andextinction of the pilot 260 meet the requirements-the sole exceptionbeing the unimportant one that the pilot will be temporarilyextinguished during the'momentary closings of stopping switch 980 by thedictator.

While it is not in general necessary in a system of this character thatthe dictator be apprized of the specific machine which is operating, oit is desirable that he be apprized of the fact that some one of thephonographs is operating when that is the case, and of the times ofshift from operation of one to operation-of another of the phonographsi:e., of the periods of overlap, or joint operation of the two phonograpTo achieve this result certain known systems have employed in theircontrol stations a plurality of phonograph pilots respectivelycorresponding to the several phonographs. According to my invention,however, this result is achieved by the single phonograph pilot 290;this is done by causing the pilot to light at one degree of brillianceduring operation of a single phonograph, and at another degree ofbrilliance during operation of two. As in the case of, the stand-bypilot the phonograph pilot may be shunted between two conductors alreadynecessary. in the control station for control purposes, this simpleconnection being caused to efi'ect' the desired results by virtue ofappropriate, but also simple, connections in the phonographs andcoupling unit. v

Thus the phonograph pilot 290, in series with a high current-limitingresistance 29l, is shunted in the control station from the startingswitch conductor 38m to the stopping switch conductor 380a. An extracontact 22a in phonograph A andan extra contact 22a. in phonograph B areprovided in alignment respectively with contacts 22 and 22' therein andadapted .to be touched by the respective arms 21 and 27' (theretoappropriately lengthened) at the same times as those contactsii. e.,when the resp'ectivearm is in run position); and the contacts 22a and22a are connected through respective conductors 292 and 292' andrespective highresistances 293 and 293' to the "ammiswmn conductor'llla.n the control arm 321 is in stop-position, the conductor we isestablished through start magnet J 32l at negative line potential; itwas seen above that conductor 38911 is then either at mid or negativeline potential (depending on the condition of the protective circuit),and accordingly the phonograph pilot 290 will receive notmore thanapproximately half line voltage and will therefore be extinguished. Ifthe control arm 921 is in run position, the conductor Illa receives nopotential through the start magnet 32l;'i! now one phonograph isoperating (the associated arm 21 or 21' being in its run position) theconductor 38in is connected to the positive conductor Ho through one ofthe resistances 299 and 292' (and one conductor 292 or 292'., onecontact 22a or 22a, and one arm 21 or 21'); but it both phonographs areoperating (both of the arms 2] and- 21' being in their run positions)the conductor go 98h: is similarly connected but through both theresistances 293 and 293' in parallel, causing an increase of the currentthrough the pilot 299. Accordingly in the three respective cases ofneither, one and both phonographs operating the phonograph pilot 299will be extinguished, lit at moderate brilliance, and lit at highbrilliancethe exception being the unimportant one that these indicationsmaybe temporarily upset during the momentary operations or the startingand stopping switches land 99. by the dictator.

The pilots thus described ere provided for the I benefit of the,dictator. It is, however, advantageous to have another set 01'indicating means for the benefit of the attendant; these means desirablycomprise an individual attendants pilot lamp for each of the severalphonographs, arranged'so that each is lit whenever the respectivephonograph is operating and so that, when the 40 In Figure 1 I haveshown the attendants pilots for the respective phonographs as 259 and259, each again preferably of the abovementioned neon type, and eacharranged to light in the recited manner. Extra contacts 22c and 220' areprovided in the respective phonographs in alignment with the contacts22-22;: and 22'22a! v therein and adapted to be touched by therespective arms at the same times as those contacts (1. 'e., when therespective arm is in run position); and each attendants pilot, in serieswith a respective high resistance 25l or 2H, is-connected from arespective one of the contacts 220 and 220' to conductor ll through arespective and so is litwhenever the respective phonograp eitheroperates or (the system being out of operation) will be the next tooperate. I have shown these connections to conductor ll, new ever, madethrough a common high resistance- 254, and this resistance shunted by aswitch formed by common control arm "Wand a contact 9220 electricallyconnected to conductor 2|! and 'mec nically incorporated in the magnetassembly I00 as ,were the contacts 22c-and 22c in the other magnetassemblies. The function of this special arrangement is to cause eachpilot'to reduce its brilliance when it is indicating merely theadaptation ofits phonograph for next operation (i. e., when control arm32'! isin stop position)this giving the attendant a visual dis- :5

mentioned in connection with the" above described indicating means-inparticular the dietators two pilots-are of values suificient to limitthe currents therethrough to materially less than required for actuationof the several start and stop magnets; typically they may haveresistance values in the tens-of-thousands of ohms.

\ In the case of phonograph pilot 290 it is desirable that resistance29| be at least as small and preferably smaller in value than each ofthe resistances 293 and 203', so that good contrast of brilliance may beobtained according to whether one, or both in parallel, of theresistances 293 and293 is effectively in series with the pilot- In thecase of the attendants pilots 250 and 250', it is"desirable that theresistance 254 be of appreciable value relative to each of theresistances 25l and 251', in order that the lamp brilliance will besignificantly varied according to the position of control arm 321.

One further indicating means for the attendant is very desirably, andwith the protective circuit according to my invention very simply,provided. This consists in a warning device for apprizing the attendantof the stoppage of the system because of lack of sound box restoration;it is provided by serially inserting in the protective circuit, forexample in conductor 51a in the coupling unit, a filamentary lamp 249 orother indicating device (audible if desired) normally operable on lowvoltage and on at least as little current as is passed through theprotective circuit during its continued closure. (When the currentrequired for normal operation of the device 240 is less than suchprotective circuit current, there is permitted the shunting of thedevice as by. a resistance 240; this has of course the advantage ofmaintaining the protective circuit operative in spite of a possible'open-circuit ing defect in the device 249.) Of course the device (asshunted if resistance 248 be employed) must be capable of withstandingmomentarily the higher current which passes through the protectivecircuit at the instant of closing thereof and before the control arm 321has thrown to stop position and reduced theprotective circuit current.

Many of theimportant features of my invention may be incorporated in analternative phonographicsystem, such as I have illustrated in Figure 2.The most essential difierence of the system of Figure 2 from that ofFigure 1 lies in the omission of the coupling unit D: andin the use ofan entirely revised control station S, which in general performs thefunctions'performed in the system of Figure 1 by the control station Cand coupling unit D together.

In Figure 2 the phonograph B and its internal wiring maybe identicalwith phonograph B of Figure 1 .(excepting for example that theprotective circuit indicating device 249 and its shunt resistance 248may be inserted in the conductor 51a within the phonograph B in view ofthe omission of the coupling unit, wherein it was before convenientlylocated). Phonograph A and its nternal wiring may likewise be identicalwith phonograph A of Figure 2, excepting that certain connections ofconductors (principally conductors leading to thecontrol station)formerly made in the coupling unit are now made in the lowerright-showncorner of phonograph A.

. In Figure 2 purely exemplary polarities have fing current.

again been noted for convenience, it being again understood that thesystem is again impervious to polarity, and may be used as well onalternat- It is now convenient to introduce the positive line conductorl2, rather than a conductor I26, directly into the two phonographs, andthis time to extend the negative line conductor to the main line switch4 in the control station. After passing through this switch (which willbe assumed closed for purposes of further description) this conductorhas been designated as Ila, and leads to the contact spring 421 of amulti-contact switch assembly 500; this spring may be considered asforming the common control arm for the system, analogous to the controlarm 321 of Figure 1. It is illustrated in stop position, to which it isbiased-i. e., out of contact with a lower-illustrated contact spring422b-but it is adapted for downward movement to close .thereagainst, andthus to come into run position, by means hereinafter described. Thecontactspring 4221) is generally analogous to the contact 3221) ofFigure 1, and to it may be led (for example out of phonograph A) theconductor Mb. I

The immediate means by which the dictator may at will position thecontrol 421 in stop and run positions are a pair of start and stopbuttons 48Ib and 480b, for example projecting up wardly through freeholes in a station top-member 50L Each button may have a respectivedownward extension 48lc or 4800 freely passing through an appropriatehole in a sub-top 502;

may be provided with a respective shoulderv ld or 480d below thetop-member and maybe biased upwardly by a respective expansion spring48le or 480e encircling its downward extension between its shoulder andthe sub-top. The start button 40lb.has a further extension or push-rod503 extending downwardly at least substantially into contact with thetop of contact spring 422- a switch 500 component hereinafter moreparticularly referred to, but here noted as positioned above control arm421 and biased to be slightly out of contact therewith when the latteris in stop position. Thus slight depression of start button 48!!) servesto close spring ,422 against control arm 421, while appreciabledepression thereof serves to move control arm 421 into run position (ofcontact with spring 4221)); if this appreciable start button depressionbe maintained against the bias of the switch springs, the arm 42 will bemaintained in run position.

Means are provided for automatically maintaining this appreciable startbutton depression. These consist in a latch 504 forming a portion of aslidable latch-plate 505 located under the sub-top, and a latch-engagingmember 505 car ried by the start button extension 4810 below thesub-top. The sliding limits of the latch-plate 505 may be established bythe longitudinal length of slots 501, through which may freely passstationary retaining screws 508; it is biased leftwardly, asillustrated, by the spring 509, and is shown in its extreme leftwardposition. As start button 48lb is depressed the member 506 causes thelatch and latch-plate to move slightly rightwardly; but as the member506 approaches the sub-latch plate edge 5"), the plate springsleftwardly again, and the latch holds the member 506 engaged, the startbutton depressed, and the control arm 421 thus in run position. The stopbutton 480!) is arranged so that its momentary depression releases thelatch and permits the arm 421 to come again into stop position inresponse may be provided with a cam-edge H; and a cam-engaging member5!?- is carried by the stop button extension 4800 so as normally to bein substantial contactwith this cam-edge. As the start button isdepressed thesliding of.memher 512 along the cam edge forces the latchplate sufliciently rightwardly so that the latch disenf gages'the member506 to release the start button, control arm 42?, etc. It will beunderstood, of course, that the shown and described arrangement oflatch-plate, and association thereof with the start and stop. buttons,is intended only to illustrate a typical means for automaticallymaintaining the start button depressed, and for releasingit in responseto stop button depression,

and that the arrangement is in no way intended as limitative,

It will now be seen that, in response to depression of start button 48thby the dictator, the control arm 42'! will come into and remain in runposition, connecting conductor Hbwith the neg ative supply line it andcausing the operation of any phonograph then having its individualcontrol arm in run position; this is of course a similar effect to thatof depression of thestart button 38]!) of Figure 1 (the only operativedistinc tion being that in Figure 2 the start button remains depressedafter the required momentary manipulation). It will-also be seen that,in response to momentary depression of stop button @062) by thedictator, the control arm Mlwill come into and remain in stop position,disconnecting conductor lib from the supply line and ping operation ofany phonograph then operating; this again is a similar eflect to that ofdepression of the stop button 300!) of Figare l. The automatic system ofstarting and stopping circuits functions in the same manner j as inFigure 1. And since the protective circuit and its functions areretained, as described immediately, hereafter, it will be seen that theuse oi. the system is quite similar to that of the system of Figure 1.As with that system, whenever the control arm 02? is in run positionthere is inv operation one (or during overlaps, two) of the phonographs;and there always remains in run tion at least one of the individual arms2?, Eli. I

Attention-may now be directed to the protective circuit in Figure 2,whichwithin the two phonographs is of course similar to that of Figare land is closed under identical conditions with those therein. Theconductor 5117 which in that figure led into the coupling unit is nowled to the control station, and in the latter is provided the device,responsive to circuit closing,

for throwing the common control arm 42! to stopposition. This device maynow-simply'comprise means for causing the latch to release the memher506; it has been illustrated inFigure 2 as a solenoid 020 arranged uponactuation to pull rightwardly a plunger 420a, of magnetic material suchas iron, secured to the latch-plate, and hence the latch-plate itself.As in Figure 1, the protective circuit is desirably completed to thenegative line conductor (in this instance to Na) through a resistancewhich is shorted out by a switch when the common control arm 42'! is inrun position. 'Ihis'resistance appears in the control station S as 496,and this switch as that formed by the spring 422, already described, andthe control arm 421.

As in the case of Figure '1 it is desirable that control;

there be provided'some means operative while the protective circuit isclosed for preventing even a temporary/starting of the motors bydepression'of the start buttoni in Flgure2 such means, in mechanicalform, are provided and operate (as in Figure 1) to prevent throwingoithe control arm 421 to run position. This means comprises a stop-edge5l3 provided on latchplate 505 to the leftof and at a higher level thanthe sub-latch plate edge' 5I0 and preferably joined therewith by a camedge 5. The range of movement of the latch-plate is made (asby the slots50'!) suiiicient so that the solenoid 420 will move it to bring thestop-edge ilsunder at least a portion of member 506; thus when thesolenoid is energized the' stop-edge 5| 3 forms a down-stop for thestartbutton 48") and prevents full depression thereof. Of course as thesolenoid acts, the opening of contact 422 from contact 021 throws inseries therewith the resistance 090; and unless this resistance be ofsuiliciently low value the solenoid energizationmill be tendered tooweakqto overcome spring 509 and the latch will return leitwardly. Butthis eflect is permissible; for in the very first portion of anyattempted re-depression of thestart button spring 822 will be closedagainst arm 421 and (if theprotective circuit still be closed) thesolenoid will be fullyenergized, instantly pulling the latch rightwardlyto get the stop-edge 5I3 under the lowering start button. (Thusresistance 496 is not necessarily provided in the protective circuit forthe purposes of the resistance inclusion therein in Figure 1; it isprimarily included for reasons, hereinafter apparent, having to do withthe indicating system.) It will now be seen that the protective circuitnot only responds as did the protective circuit 01 Figure 1, butproduces the same ultimate eilectsas did that circuitthough by somewhatdifierent. means, appropriate to the altered dictator's control system.

' The prevention of, temporary phonograph starting by start buttondepression while the protective circuit remains closed may if desired beaccomplished alternatively by electrical rather than mechanical means;this has been illustratedin Figure 2a-a fractional control station viewintended for optional substitution for the corresponding'portion ofFigure 2. Herein the possible rightward latch-plate movement may belimited to just enough for dependable latch release, as by theemployment of restricted-length slots 501'; and the stop-edge M3 (andcam-edge 5H joining it with sub-latch edge 5l0) need not be provided.While the protective circuit device for releasing the latch may be thesolenoid 420 of Figure 2, it is permissible in view of the restrictedlatch-plate movement to employinstead thereof an electromagnet; this hasbeen illustrated as 520, having fixed core 5200, and arranged uponenergizatloii to attract an armature 520a secured to the'latch-plate andhence the latch-plate itself. The electrical means for preventingimproper motor starting consists simply in a switch 5), having the\pole. 5|9a biased to close the switch, and serially inserted in theconductor lib; the

pole 5|9a is arranged to be'moved by rightward plate rightwardlyattracted, switch 9 open, and the phonographsithus incapable ofstarting.

There remain finally to be considered in Figure 2 (or 2a) the attendantsand dictators indicating means; these have been somewhat differentlyincorporated both for the purpose, in the case of the dictators means,of a simplification appropriate to the revised control station, andgenerally for the purpose of minimizing the number of conductorsrequired to and from the control station.

The attendant's warning device 249 has already been mentioned. Theattendants pilots 250 and 250', each in series with the respective highresistance 251 or 251', are inserted as before in the respectiveconductors 252 and 252' and each of these conductors connected at oneend to the respective magnet assembly contact 220 or 220. At their otherextremities, however, these conductors are not connected to the negativesupply line in the manner shown in Figure 1, but are connected with thatprotective circuit conductor51bwhich extends to the control station.Solong as the protective circuit is open this conductor is rendered atnegative line potential, either through the solenoid 420 only if thecontrol arm 421 is in run position and thus at least one phonographoperating, or through the solenoid and resistance 495 if the control armis in stop position and thus neither phonograph operating. Thus thesepilots will be lit at the same times as in the case of Figure lsub;lectonly to the exception that they will be extinguished when the protectivecircuit is closed (by virtue of a then positive potential of conductor51b), at which time the attendant however has the then most essentialindication provided by the warning device 249. And the resistance 495,of course in increasing degree as it is made larger, provides, as inFigure 1, some contrast of brilliance between operation andadaptation-for-next-operation indications.

In the system of Figure 2 up and down positions of the start button 49lbthemselves form indications of phonograph operation and nonoperation; incombination, then, with such an indication I have combined for thedictator the indications of a single pilot 559. When the start button isdepressed, illumination of this pilot at a I moderate brillianceindicates that one phonograph is operating and illumination at highbrilliance that two are operating; when the start button isgup anyillumination of this pilot indicates readiness of the system foroperation upon depression of that button. To achieve this result Iconnect one terminal, of the combination of pilot 56ll and its serieshigh resistance 55!, to a conductor 559 leading therefrom for exampleinto phonograph A, and to this conductor I connect the conductors 292and 292' of 'Figure 1 (each of which leads through a respective highresistance 293 or 293' to a respective magnet assembly contact 22a or22a) The other terminal of the pilot-resistance combination 550-5 Iconnect to negative conductor I la when the control arm 421 is in runposition, and to the conductor 511) when that arm is in stop position.In the run position case the combination is therefore connected acrossthe supply linethrough one of the resistances 293 and 293' if onephonograph operates (one arm 21 or 21' in run position), and throughboth of these resistances if both phonographs operate (both arms 21 and21' in run position), thus providing the contrast of brilliance. In thestop position case the combination is connected, through one or both ofthe resistances 293 and 293' and through solenoid 420 and resistance496, across the line so long as the protective circuit is open and thesystem thus in readiness for operation upon'start button depression; if,however, the protective circuit is closed and the system thusinoperable, conductor 51b is at positive potential and no voltageappears across the pilot to illuminate it. The selective connection ofthe second-mentioned terminal of the pilot-resistance combination 56059lmay be effected by a contact spring 552 included in the switch assembly500 below arm 421, and to which that terminal is wired; when arm 421 isin stop position this spring is touched from underneath by a contactspring 563, which is wired to conductor 51b. The spring 563, however, islinked to the arm 421 by an insulating tierod or -block b"; and when arm421 is moved downwardly to run position it both moves spring 553 out of,and itself comes into, contact with spring 562.

While throughout the specification I have described the phonographicsystems and their operations, and the various features of my invention,in terms of specific embodiments thereof, I intend thereby no.unnecessary limitations; rather I intend in the appended claims to claimmy invention, and all its novel sub-combinations, elements andindividual features, as broadly as the state of the art will permit.

1 claim:

1. In combination, a plurality of phonographs, each having a sound boxelement adapted for progressive movement relative to a record element;an automatic control systemfor maintaining said phonographs insequential operation; other control means connected in common with allphonographs; and means, responsive to said elements when they becomeadjacent their respective movement limits in all phonographs, foractuating said common means to place all phonographs out of operation.

2. In combination, a plurality of phonographs, each having a sound boxelement adapted for progressive movement relative to a record element;an automatic control system for maintaining said phonographs insequential operation; other control means connected in common with allphonographs and actuable selectively to initiate said phonographoperation and place all phonographs out of operation; and means,responsive to said elements when they become adjacent their respectivemovement limits in all phonographs, for blocking actuation of saidcontrol means which initiates phonograph operation.

3. In combination, a plurality of phonographs I arranged for sequentialoperation, each having a sound box element adapted for progressivemovement relative to a record element; control means connected in commonwith all phonographs and actuable selectively to initiate saidphonograph operation and place all phonographs out of operation; andmeans, responsive to adjacency of said elements in all phonographs totheir respective movement limits, for actuating said control means toplace all phonographs out of operation and for blocking actuation ofsaid control means to initiate phonograph operation.

4. In combination, a plurality of phonographs each having a sound boxelement adapted for progressive movement relative to a record element;an automatic control system energizable to maintain said phonographs insequential phonograph operation; a single switch throwable to energizeand to, de-energize the entire said system; and means, responsive tosaid elements when they become adjacent their respective movement limitsin all phonographs, for throwing said switch to de-energize said system.

5. In, combination, a plurality of phonographs each having a sound boxelement adapted for progressive movement relative to a record element;individual control means for each phonograph; an automatic systemarranged for energization to actuate the several individual means forsequential phonograph operation; a control means connected in commonwith all phonographs; and means, responsive to adjacency of saidelements in all phonographs to their respective movement limits, foractuating said common means to place all phonographs out of operation.

6. In combination, a plurality of phonographs each having a sound boxelement adapted for progressive movement relative to a record element;an automatic control system energizableto maintain said phonographs insequential operation; other control means connected in common with allphonographs; and means, responsive to said elements when they becomeadjacent their respective movement limits in all phonographs, forde-energizing said automatic sys tem and actuating said common means toplace all phonographs out of operation.

7- In combination, a system of phonographs each operable for limitedrecord traversal;

means for operating said phonographs in predetermined mutualrelationship; a control device connected in common with all saidphonographs; and a protective circuit and means for closing the same inresponse to a condition of substantial completion of said traversals inall phonographs, said,-protective circuit serially including a source ofcurrent and current-responsive means for actuating said control deviceto place said system out of operation.

In combination, a system of phonographs -each operable for limitedrecord traversal;

means for operating said phonographs in predetermined mutualrelationship; a control device connected in common with all saidphonographs;

. and a protective circuit and means for closing the same in response toa condition of substantial completion or said traversals in allphonographs, said protective circuit serially including a source ofcurrent, an indicating device, and

current-responsive means for actuating said control device to place saidsystem out of operation. a

In combination, a system of phonographs each having a sound box elementarranged for progressive movement relative to a record element; aprotective circuit interlinking the several phonographs; means,responsive to adjacency of said elementsin'all phonographs to theirrespective movement limits, for closing said circuit; and means,responsive to closing of said circuit, for placing said system out ofoperation.

1 In combination, a system of phonographs each having a sound boxelement arranged for progressive movement relative to a record element;a normally open switch in each phonograph arranged to be closed as saidelements approach their movement limit; and a protective circuitserially including all said switches and means responsive to their jointclosing for placing said system out of operation.

11. In combination, a plurality of phonographs each having a sound boxelement adapted for the one phonograph; switch means in each 10phonograph arranged for closing before operation of said actuating meanstherein; and a protective circuit serially including said switch meansof all phonographs and means responsive to the joint closing of all saidswitch means for 15 placing said system out of operation.

12. In combination, a plurality of phonographs each operable for limitedrecord traversal; means for operating said phonographs in predeterminedmutual relationship; throwable control member having, run and stoppositions, connected in common with all said phonographs; a protectivecircuit and means for closing the same in response to a condition ofsubstantial completion of said traversals in all phonographs;electromagnetic means for throwing said control member to stop'position,and means for passing an, actuating current therethrough upon closing ofsaid circuit; and means operative after initial closing and duringcontinued closing of said circuit for passing through saidelectromagnetic means a reduced current of suflicient strength tomaintain said control member in stop position.

13. In combination, a plurality of phonographs; an individual controlmember for each phonograph having run and stop positions; a system forautomatically moving sai members for sequential phonograph operationwhile at any time leaving at least one of said members in run position;control means connected in common with all phonographs for causing andstopping phonograph operation; and common indiindicating device andmeans for passing current therethrough; and means responsive to thenumber of phonographs operating for regulating said current.

15. In combination, a plurality of phonographs each operable for limitedrecord traversal; means 55 for operating the same in predeterminedmutual relationship; means comprising a protective circuit for placingall said phonographs out of operation in response to a condition ofsubstantial completion of said traversals in all phono- .0

graphs; an indicating lamp having a minimum ignition voltage, and meansnormally operative to impress a higher voltage thereacross; and meansresponsive to protective circuit operation for reducing the voltageacross said lamp to a finite voltage less than said minimum ignitionvoltage.

16. In combination, a plurality of phonographs each operable for limitedrecord traversal; an 70 individual operation control member for eachphonograph; means for moving said members to operate said phonographs inpredetermined mutual relationship; a switch connected in common with allphonographsand movable at will to a selectively g0 run and stoppositions; protective circuit means for throwing said switch to stopposition in response to a condition of substantial completion of saidtraversals in all phonographs; an indicating lamp and means forilluminating the same; and selective means associated with said switch,operative when said switch is in run position to render said lampresponsive to said individual control members, and when said switch isin stop position to render said lamp responsive to said protectivecircuit.

17. The combination according to claim 9, further including anindicating device responsive to the condition of said circuit.

18. In combination, a plurality of phonophonograph will first operateupon resumption of said sequential operation.

19. In combination, a plurality of phonographs each having a sound boxelement adapted for progressive movementrelative to a record element; acommon circuit for supplying power to said phonographs; an automaticcontrol system for maintaining said phonographs in sequential operation;and other control means, responsive to said elements when they becomeadjacent their respective movement limits in all phonographs, forbreaking said common circuit.

20. In combination, a plurality of phonographs each having a sound boxelement adapted for progressive movement relative to a record elegraphs;means for maintaining said phonographs ment; a common circuit forsupplying power to 1) in sequential operation; means movable to causesaid phonographs; an automatic control system the suspension andresumption of said operaenergizable to maintain said phonographs insetion; indicating devices for the several phonoquential operation; andother control means, regraphs respectively and means for passingcursponsive to said elements when they become ad- 20 rent through eachsaid device when its said respective phonograph is operating; and means,rendered operative by an operation-suspending movement of said movablemeans, for passing a modified current through that device whoseCERTIFICATE Patent No. 2,lh6,l .5h..

' CHARLES It is hereby certified that error appears in the pr of theabove numberedpatent requiring correction as column, line 5.9, forcontact 2". read contact 22';

jacent their respective movement limits in all phonographs, for breakingsaid common circuit and de-energizing said automatic system.

CHARLES T. JACOBS.

inted specification follows: Page i firstpage 5, second column,

line 1+5, after "dictator" insert may; page 7,.second column, line 27,after "control" insert arm; page 9, second column, line 5h, claim 2,after blocking" insert that, and that the said Letters Patent shouldberead with this. correction therein that the same may conform to therecord of the case in the Patent Office.

.Signed and scared this llth day of April, A. D. 1959.

Henry Van Arsdale Acting Commissioner of Patents.

